If he gets a non-Retina MBP, he can remove the optical drive and install a 2nd hard drive. I did it on my non-Retina MBP and installed Windows on it; works great.
Of course the real limiting factor, as far as gaming goes, is the integrated graphics. While I was continually impressed with the ability of the Intel HD 4000 to run games I was certain didn’t have a chance in hell of running (Tomb Raider, Hitman: Absolution, Batman: Arkham City, and Splinter Cell: Conviction all ran), rarely did they play at anything better than barely playable framerates even at the lowest settings.
He can get the RAM upgraded (though, as mentioned upthread, aside from the non-Retina MBP this is not user-upgradeable, it must be done at purchase), and get a bigger SSD installed, but at that point he’s looking at an extra $700 on top of what’s already an $1800 machine (only the 2.6GHz Retina MBP has the option to upgrade the storage, and apparently, like the RAM, cannot be done by the user on the newest machines). For half that kind of money he could get a ridiculous PC laptop.
Now, if he’s gaming at home he could install games on his desktop and do the Steam stream thing to the laptop, but if he’s already home, why? (this is something I’ve not been able to figure out the purpose of, but perhaps that’s a different discussion)
I have merged two duplicate threads (one from GQ and the other from IMHO) together into one thread. This may cause a bit of confusion with some of the posts.
If he wants to play games other than app-type games (and who knows what he means “pretty heavy computer gamer”) then he’s going to need a model with a real graphics card. That means the only possible option for a Mac laptop is the 15" 2.3GHz with Retina Macbook Pro. All the other models, including the entire Air line, use integrated Intel graphics (that’s how they get it so small, fyi).
Which starts at $2599. Which is why I never, ever, recommend a Mac laptop for a PC gamer.
But at any rate, before you buy something off the shelf, he should contact his department and ask them what to get. They might have special discounts and required hardware/software packages. Check with them first.
I’d go with the MacBook Air. He can install Windows and Linux on it as well, and boot into them natively, or run them in an emulator.
This way, he has all three of the major OSs, plus running on some of the best hardware. Hard to go wrong with a Mac.
ETA: MBPro has better Video Card options for gaming.
Let’s assume the OP’s brother now has his Mac. What other tools should this promising Grad acquire to help further his endeavour? Maybe a slide rule emulator? Or possibly, a virtual deck of “Punched Cards”.